Fabrication Of Silicon Nanostructures By Wet Etching And Application In Silicon/PEDOT:PSS Hybrid Solar Cells

Nanostructured silicon(Si)/poly(3,4-ethylene dioxythiophene): poly(styrenesulfonate)(PEDOT:PSS)hybrid solar cells have the potential to achieve excellent device performance due to utilizing high mobility of crystalline Si,and effective light management of nanostructured Si,and well simple solution fabrication process of organic thin film materials.In this paper,the hybrid solar cell is investigated through spin-coating PEDOT:PSS onto different nanostructured Si,which is prepared by wet etching on cheap substrate.General research ideas are summarized to achieve high performance of nanostructured Si/PEDOT:PSS solar cell.And the research work mainly includes the following aspects:(1)Si nanowires(NWs)with various feature sizes are developed on single crystal n-Si surface using wet etching in HF/AgNO3 solution,and the influence on the performance of solar cell is investigated.SiNWs/PEDOT:PSS hybrid solar cell delivers a power conversion efficiency(PCE)of 7.1%(short circuit current density(Jsc): 33.91 mA/cm2,open circuit voltage(Voc): 0.46 V,fill factor(FF): 0.45).For Si NWs/PEDOT:PSS hybrid solar cell,only through regulating feature sizes of SiNWs,it can not effectively improve the contact interface between PEDOT:PSS and nanostructured Si and obtain the high quality electrode preparation,thus leading to the inferior Voc and FF of SiNWs/PEDOT:PSS solar cell.(2)To improve Voc and FF of SiNWs/PEDOT:PSS solar cell,an inverted Si nanopyramid(iSiNP)surface structure with low aspect ratio is developed through sequential treatments to the SiNW-textured surface by NaOH and HF/CH3COOH/HNO3 solutions.Owing to the low aspect ratio,the iSiNP-textured surface can be conformally covered by PEDOT:PSS,thus forming a high quality junction and contact,as compared to the high aspect ratio Si NWs/PEDOT:PSS solar cell.In the meantime,it is found that the performance of iSiNPs/PEDOT:PSS solar cell is improved due to the high-quality electrode contact compared with Si NWs/PEDOT:PSS.Without any further optimizations,the iSiNP/PEDOT:PSS hybrid solar cell delivers a PCE of 9.6%(Jsc: 29.74 mA/cm2,Voc: 0.53 V,FF: 0.61).(3)In order to reduce the material cost,Si NWs are prepared by wet etching on the thin film Si coated glass substrates.First,the high-quality crystalline Si thin film is deposited on glass by thermal chemical vapor deposition through optimizing the experimental conditions.Then,SiNWs are prepared by wet etching on glass substrate without damaged using the certain protective measures.This fabaircation method greatly reduces the use of Si materials as compared to general preparation on the crystalline Si.It is expected to be applicable to high efficient and low cost Si/PEDOT:PSS solar cells.